Lava doesn’t care about your timeline. It cools when it wants to cool, hardens when it feels like it, and becomes soil—well, that part takes a geological forever. Except when fungi show up.
When Rocks Become Real Estate for Microscopic Squatters
Here’s the thing about fresh lava flows: they’re about as hospitable as a blast furnace. In 2018, when Kilauea volcano in Hawaii vomited out enough molten rock to fill 320,000 Olympic swimming pools, scientists assumed the new landscape would sit sterile for decades. They were wrong. Within months, fungal spores had colonized the barely-cooled basalt, doing something that sounds like science fiction—literally eating rock.
Fungi don’t have teeth, obviously.
But they’ve got something better: acids. Species like Penicillium and Aspergillus secrete oxalic acid and citric acid, the same stuff that makes lemons sour, except these microorganisms weaponize it. The acids dissolve minerals locked in volcanic glass—pulling out iron, magnesium, calcium, phosphorus. A 2019 study published in Frontiers in Microbiology documented how mycorrhizal fungi at Mount Etna in Sicily, a volcano that’s been erupting for roughly 500,000 years, accelerated basalt weathering by 340% compared to non-colonized rock. That’s not a typo. Three hundred and forty percent.
Wait—maybe that sounds abstract. Let’s get concrete: without fungi, a lava flow in Iceland might take 10,000 years to break down into something resembling soil; with aggressive fungal colonization, that timeline collapses to a few centuries. Researchers studying the 1783 Laki eruption in Iceland—which killed 20% of the island’s population through famine—found that areas where lichens (fungal-algal partnerships) established early now have topsoil depths exceeding 30 centimeters, while barren zones remain essentially moonscapes.
Turns out fungi are basically geological hackers, cracking open minerals like safes.
The Metabolic Weirdness That Makes Mountains Edible Eventually
Nobody teaches you in school that rocks are nutritious, because for most organisms, they’re absolutely not. But fungi operate on different rules. They extend thread-like hyphae into microscopic cracks in cooled lava, and through a process called biomineralization, they don’t just extract nutrients—they transform the rock’s actual structure. A landmark 2016 paper in Nature Geoscience showed that certain basidiomycete fungi in Hawaii’s 1959 Kilauea Iki lava lake were producing clay minerals as metabolic byproducts. Clay. From lava. In less than sixty years.
The fungi aren’t being altruistic, obviously—they’re mining the rock for phosphorus and trace metals they can’t get elsewhere in these barren hellscapes. But their selfish chemistry creates the foundation for everything else: mosses, ferns, eventually shrubs and trees. When Mount St. Helens erupted in 1980, obliterating 230 square miles of forest, mycorrhizal fungi were among the first colonizers detected in the pumice plains. By 1988, just eight years later, scientists documented 30 different fungal species actively breaking down volcanic ash and lapilli, creating nutrient patches where lupines—nitrogen-fixing plants—could establish.
That’s about as close to ecological alchemy as nature gets, turning sterile slag into living soil through microscopic acid trips (the chemical kind, not the psychedelic kind, though some volcanic fungi do produce interesting compounds—whole different article). The process is slow by human standards but blazing fast geologically. Paricutin volcano in Mexico emerged from a cornfield in 1943, and by the 1970s, fungi had colonized its flows so aggresively that researchers found measurable soil development on slopes that had been molten rock within living memory.
The metabolic machinery involved is genuinely bizarre: siderophores that chelate iron, melanin pigments that protect against UV radiation on exposed rock faces, enzymes that literally pry silicon-oxygen bonds apart. These aren’t plants photosynthesizing peacefully—these are chemical warfare specialists conducting controlled demolitions on planetary scale.
And we’re only beginning to catalogue which species do what, where, and how fast, because until recently nobody thought to look closely at who’s living on year-old lava.
